System for fluid sterilization for a vessel

ABSTRACT

A system of fluid sterilization of fluid of vessel is provided, such as sterilization of ballast water for a water vessel. The system incorporates a heating section to heat pressurized fluid above prescribed thresholds for temperature, pressure, and duration (e.g., dwell time) to achieve desired levels of sterilization, including a heat exchanger to both (a) preheat fluid prior to entering the heating section and (b) cool outflow of the heating apparatus, in which fluid travels through the apparatus by operating valves forward and aft of the heating section in a controlled sequence to facilitate flow through the system while maintaining prescribed pressure and temperature profiles. The system operates within prescribed ranges of pressure and temperature to achieve the desired level of sterilization without need of maintaining a fixed temperature or a fixed pressure within any portion of the system, including the heating section.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation-in-part of U.S. application Ser. No.15/664,868, filed Jul. 31, 2017, which is a continuation of U.S.application Ser. No. 15/249,097, filed Aug. 26, 2016, which claims thebenefit of U.S. App. No. 62/211,576, filed Aug. 28, 2015, all of whichare incorporated by reference.

FIELD OF THE INVENTION

The present invention relates generally to fluid purification andsterilization and, more particularly, to purification and sterilizationby heating fluid above thresholds for temperature, pressure, andduration (e.g., dwell time) for use on board vessels.

BACKGROUND OF THE INVENTION

Fluid sterilization plays an important role across a wide spectrum ofapplications, to include personal, industrial, manufacturing, andmedical applications. Generally speaking, sterilization is identified asa process that will make an object free of any living transmissibleagent (such as fungi, bacteria, viruses, spore forms, microorganisms,prions, etc.). The object to be sterilized may be any of several types,including surfaces, a volume of fluid, or other materials in use or tobe used in human or animal activities. Effectiveness of sterilization isgenerally referenced via a sterility assurance level (SAL).

Moreover, the issue of aqueous fluid sterilization is one of growingimportance to both the developed and developing world alike.Complications resulting from contact with bacterially contaminated waterare some of the leading causes of illness in the developing world.Further, it is one of the leading causes of death amongst children inthe developing world.

Current challenges embodied in present sterilization operations of waterleave much room for improvement. Most clean water systems today usesterilization processes such as reverse osmosis, membrane (filter)technology, or UV light technology. These systems require regularmaintenance, a large amount of energy, and routine replacement of majorcomponents, such as membranes, filters or UV bulbs. As such, they areexpensive to operate and maintain, particularly for high volumeapplications. Another solution involves the heating of the water to ahigh temperature as a means to sterilize, which typically requires largeheat-sink apparatus to contain and cool the water after heating.

Both approaches necessitate the apparatus to be structurally large andgenerally immobile. Further challenges involve solutions using anon-continuous flow of the fluid, by-product being created by theprocess necessitating more maintenance, and the limitation to processonly water.

Additionally, as invasive medical procedures become more commonplace androutine, the growing contact of foreign instruments with the relativelyunprotected interior of human bodies greatly increases the need ofproper instrument sterilization. Current solutions typically involvesterilization through immersion in disinfecting solutions (e.g., alcoholor bleach), ultrasonic methods (produce cavitation via high frequencysound waves) to clean, or exposure to high temperature in the form ofhigh-pressure steam. These solutions have their limiting challenges:disinfecting solution methods produce harmful waste with limited re-use;the ultrasonic process is time intensive and demanding of both energyand maintenance; and high-pressure steam solutions can potentiallydamage sensitive and fragile equipment and special equipment with highpressure seals, etc. Most current solutions contain a number of movingparts, the addition of each creating the added issue of maintenance, andrisk of possible contamination.

Further, contaminants such as “prions” are very difficult to kill andresistant to virtually all current sterilization methods. Prions areproteins that are folded in structurally distinct ways, which can betransmissible to other proteins, causing these other protein moleculesto adopt such distinctive folding. Such misfolded protein replicationwithin humans and other mammals can be harmful, particularly to brainand nervous tissue. This form of replication leads to disease that issimilar to viral infection.

A protein as an infectious agent stands in contrast to all other knowninfectious agents, like viruses, bacteria, fungi, or parasites—all ofwhich must contain nucleic acids (DNA, RNA, or both). In many instances,prions in mammals can have deleterious consequences, such as damage tobrain and neural tissue, which are currently untreatable, other thancomplete removal of the infected tissue from the patient. Equipment andinstruments used for such treatment must thereafter be consideredcontaminated.

Current procedures for decontaminating medical equipment are ineffectiveat reliably eliminating or inactivating prions to a medically acceptablelevel. As such, current protocols commonly call for disposal anddestruction of medical equipment exposed to prions, which is anexpensive proposition.

In yet other applications, ocean ships and other water vessels employballast tanks that may intake water from one port, and subsequentlydischarge the water in another port, for stabilization of the vessel,wherein such stabilization can be a function of the weight onboard, andcan take into account weight fluctuations, for e.g. due to theloading/unloading of cargo. However, discharging water collected from aforeign port into a local port can potentially introduce foreignbiological matter into the ecosystem of the local body of water, therebyharming its vitality. As such, governing agencies across the world,including the U.S. Coast Guard for the United States have established asterilization level that must be adhered for all water vesselsdischarging such water within the ballast tanks. Although currentmethods exist to achieve this level of sterilization, such as using UVlight, such methods can be inefficient, and sometimes ineffectiveparticularly when targeting large microorganisms.

Therefore, it should be appreciated there remains a need for anapparatus and method which can produce sterile fluid for a variety ofuses, such as, to sterilize contaminated instruments and equipment to adegree not possible with current approaches.

SUMMARY OF THE INVENTION

Briefly, and in general terms, the invention provides a system andmethod of fluid sterilization which incorporates a heating section toheat pressurized fluid above prescribed thresholds for temperature,pressure, and duration (e.g., dwell time) to achieve desired levels ofsterilization, including a heat exchanger to both (a) preheat fluidprior to entering the heating section and (b) cool outflow of theheating apparatus, in which fluid travels through the apparatus byoperating valves forward and aft of the heating section in a controlledsequence to facilitate flow through the system while maintainingprescribed pressure and temperature profiles. The system operates withinprescribed ranges of pressure and temperature to achieve the desiredlevel of sterilization without need of maintaining a fixed temperatureor a fixed pressure within any portion of the system, including theheating section.

More specifically, in an exemplary embodiment, the system incorporates aplurality of valves coupled to a controller such as a computer,including valves disposed at inlet and outlet points of the heatexchanger and at inlet and outlet points of the heating apparatus. Thevalves are operated in a controlled sequence to enable effectiveoperation of the system to include maintaining fluid within the heatingassembly for the desired duration to achieve sterilization. Thereafter,inlet and outlet ports are opened in a sequenced manner to enable thefluid to exit heating assembly while creating a draw of received fluidfrom the heat exchanger into the heating apparatus. The system canutilize a controller that implements proprietary software forcontrolling system operations, including controlled sequence of thevalves.

In a detailed aspect of an exemplary embodiment, the system can beoperated free of pumps, while achieving the desired pressure levels dueat least in part to controlled sequence operation of the valves via thecontroller. Inlet water pressure is preferably at a minimum level.

In another detailed aspect of an exemplary embodiment, the apparatus mayfurther recirculate fluid to sterilize system pathways and/or mayinclude an autoclave chamber to sterilize equipment.

In another detailed aspect of an exemplary embodiment, the apparatus mayfurther include pipes running in parallel through the heat exchanger andthe heating section.

For purposes of summarizing the invention and the advantages achievedover the prior art, certain advantages of the invention have beendescribed herein. Of course, it is to be understood that not necessarilyall such advantages may be achieved in accordance with any particularembodiment of the invention. Thus, for example, those skilled in the artwill recognize that the invention may be embodied or carried out in amanner that achieves or optimizes one advantage or group of advantagesas taught herein without necessarily achieving other advantages as maybe taught or suggested herein.

All of these embodiments are intended to be within the scope of theinvention herein disclosed. These and other embodiments of the presentinvention will become readily apparent to those skilled in the art fromthe following detailed description of the preferred embodiments havingreference to the attached figures, the invention not being limited toany particular preferred embodiment disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described, by way ofexample only, with reference to the following drawings in which:

FIG. 1 is a simplified block diagram of a first embodiment of a fluidsterilization assembly in accordance with the present invention.

FIG. 2 is a simplified block diagram of a second embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating electric immersion heaters as heating apparatus.

FIG. 3 is a simplified block diagram of a third embodiment of a fluidsterilization assembly in accordance with the present invention,including pipes running in parallel through the heat exchanger and theheating section.

FIG. 4 is a simplified block diagram of a fourth embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating an autoclave chamber using fluid.

FIG. 5 is a perspective view of a fifth embodiment of a fluidsterilization assembly in accordance with the present inventionillustrating an arrangement of valves.

FIG. 6 is a simplified block diagram of a sixth embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating a cooling section and an inductive heat exchanger as aheating element.

FIG. 7 is a simplified block diagram of a seventh embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating a cooling section and an alternate possible arrangement ofvalves and sensors.

FIG. 8 is a simplified block diagram of an eighth embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating a pre-heating section as well as a cooling section.

FIG. 9 is a simplified block diagram of a ninth embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating a surface heat exchanger as a heating element.

FIG. 10 is a simplified block diagram of a tenth embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating immersion heat exchangers as heating apparatus.

FIG. 11 is a simplified block diagram of an eleventh embodiment of afluid sterilization assembly in accordance with the present invention,incorporating a propane-based heater and thermoelectric generators.

FIG. 12 is a simplified block diagram of a twelfth embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating an autoclave chamber with electric immersion heaters.

FIG. 13 is a perspective view of a thirteenth embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating a controller to read sensors and actuate valves.

FIG. 14 is a front view of the fluid sterilization assembly depicted inFIG. 13.

FIG. 15 is a top view of the fluid sterilization assembly depicted inFIG. 13.

FIG. 16 is a rear view of the fluid sterilization assembly depicted inFIG. 13.

FIG. 17 is a bottom view of the fluid sterilization assembly depicted inFIG. 13.

FIG. 18 is a different perspective view of the fluid sterilizationassembly depicted in FIG. 13.

FIG. 19 is a top view of one configuration of the propane-based heaterutilized in the embodiment depicted in FIG. 11.

FIG. 20 is a variation on the embodiment depicted in FIG. 2 using abifurcated immersion heater system.

FIG. 21 is a simplified block diagram of system operation in accordancewith the invention, e.g., with reference to the assembly of FIG. 9.

FIG. 22 is a perspective view of another embodiment of a fluidsterilization assembly in accordance with the present invention,incorporating a gas heater.

FIG. 23 is a simplified block diagram of machine states for systemoperation in accordance with the invention.

FIG. 24 is a side view of a propane-based heater that can be used in aheater assembly of a fluid sterilization assembly in accordance with theinvention.

FIG. 25 is a side view of another propane-based heater that can be usedin a heater assembly of a fluid sterilization assembly in accordancewith the invention.

FIG. 26 is an exemplary screenshot of a status monitoring screen of thefluid sterilization assembly of FIG. 22.

FIG. 27 is a simplified flow chart of system status operations of thefluid sterilization assembly of FIG. 22.

FIG. 28 is a simplified block diagram of a fourteenth embodiment of afluid sterilization assembly in accordance with the present invention,incorporating a water heater system employing waste heat recoverymethods to sterilize the fluid from a ballast tank system.

FIG. 29 is a simplified block diagram of a fifteenth embodiment of afluid sterilization assembly in accordance with the present invention,depicting a water heat exchanger immersed within a ballast tank.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The term “fluid” as used herein is defined to include any gas or liquidcapable of flowing through the system, including water or aqueoussolutions such as juice or milk, and liquids or gases with dissolved orsuspended solids such as flue gas or crude oil or wastewater, e.g.,black water or grey water.

Referring now to the drawings, and particularly FIGS. 1 and 2, there isshown a fluid sterilization assembly usable for sterilizing water. Afluid source 10 is connected to an inlet of the assembly. The systemuses high temperature to sterilize the fluid to a desired level. Thissterilized fluid then has a variety of uses, one of which being theproduction of decontaminated drinking water no matter the level ofbiological contamination or source. Sterilization is achieved by passingthe fluid through a heating element to super heat the fluid to such adegree as to sterilize any living transmissible agents. The systemoperates within prescribed ranges for pressure and temperature toachieve the desired level of sterilization without need of maintaining afixed temperature or a fixed pressure within any portion of the system,including the heating section. Moreover, inlet pressure of the fluidenables flow through the system.

Operation of the assembly can include a start-up phase, a continuousflow phase and an operations phase. In the start-up phase, fluid isinitially introduced into the system, sterilized, resides for a shorttime, and primes the system for continuous flow operation. In theoperations phase, sterilized fluid is directed for use, e.g., see FIG.23 for various operational states for the assembly.

The assembly in FIGS. 1 and 2 contains an inlet for the fluid, whichcomprises a valve assembly 11. The fluid continues along the flow pathto a first (cool) path portion of a heat exchanger 12, in which thefluid is pre-heated, before it travels along the flow path to a heatingsection 14, where the fluid is heated to a prescribed temperature andpressure for a prescribed duration (e.g., dwell time) to sterilize thefluid to above a desired level. Thereafter, the fluid then travels alongthe flow path back through a second (hot) path portion of the heatexchanger 12 to cool before it exits the system. During the start-upphase, fluid exits the system through valve assembly 18 as off-specdischarge 19. During the operation phase, the fluid exits the systemthrough valve assembly 17 as sterile fluid discharge 20. Discharge offluid from the system can create a draw of more fluid into the system,to contribute to flow of contaminated fluid into the system, anddischarge of sterilized fluid. Moreover, inlet pressure of the fluidenables flow through the system.

The exemplary embodiment utilizes several valves of different types atseveral dispositions in order to maintain a desired operating range ofprocess variables, such as flow rate or pressure. The specific number,use, and disposition of valves in the embodiments herein is describedfor illustrative purposes only, and is not to be understood as limitingthe present invention to these specific numbers, uses, or dispositionsof valves. Various types of valves, including the check valves,proportional flow valves, solenoid valves, and relief valves describedin the exemplary embodiments, may be added or removed at variousdispositions in the system with similar functionality. For example,servo valves may be used in place of or in addition to latch valvesdescribed in the exemplary embodiment, and may be disposed anywherealong the flow path of the system, or may be eliminated from the systemaltogether. As another example, stepper motor proportional flow valvesmay be used in place of or in addition to pilot-operated proportionalflow valves, used with or without pressure transducers or flow meters.Furthermore, the valves in the system may be actuated by hand, byspring, by solenoid, or by any other means of valve actuation.Similarly, the number and disposition of thermocouples, pressuretransducers, and process sensors or other control-related apparatusother than valves may be altered from the descriptions herein withoutdeparting from the scope of the present invention. Moreover, the heatingcomponents can be insulated to inhibit radiant heat loss. Various formsof insulation can be used, such as, e.g., ceramic layer can be used,which can provide additional benefits. For example, immersion heaterscan be provided with a ceramic coating, which can further inhibitscaling (build up) on the heaters, over extended use.

A controller or controllers 180, disposed internally or connectedexternally to the system, interfaces with valves, transducers,thermocouples, or sensors in the system. The controller 180 in theexemplary embodiment is a digital computer comprised of a microprocessorthat executes computer readable instructions to coordinate the operationof the system; however, any device capable of process control may beused, including, but not limited to, mechanical or pneumaticcontrollers, or analog electronic systems. The use of controllers couldenable an operator to observe and manage the sterilization process(e.g., reading sensor data from a user interface or display, and openingor closing valves accordingly), or could enable the system to operateautonomously under prescribed operational guidelines. Controllers may beused to a limited degree, or may be used to such an extent that thesystem would merely need to be powered on in order to produce sterilizedfluid according to specification. Embodiments of the system may be usedwithout controllers, however, such that an operator could manuallyactuate valves and read sensors information, i.e., gauges or visualreadouts or graphics.

More particularly, and with continued reference to FIG. 2, fluid entersthe system from the inlet 30 through a hand valve (HV1) 31. In theexemplary embodiment, the fluid has a pressure between 50 psig and 500psig, and travels through a check valve (CV1) 35, a pressure transducer(P1) 36, a thermocouple (TC1) 37, and a flow meter (FM1) 38.Additionally or alternatively, a pump 34 may be used to draw fluid froma reservoir or other source of unpressurized fluid through an inlet 32.Check valves are used to ensure unidirectional flow in the system, andpressure transducers and thermocouples, as well as other sensors, areused to monitor the dynamic properties of the fluid in the system. Flowmeters are used to determine the rate of fluid passing through thesystem, which can be altered using proportional flow valves. The inletfluid pressure defines the flow rate and the residence time at thesterilization temperature, according to the applicable sterilizationtemperature. Table 1, below, lists sterilization temperatures for giveninlet pressure in an exemplary embodiment.

TABLE 1 Inlet Pressure Boiling Point Sterilization Temperature (psig) (°C.) (° C.) 10 115 108 50 147 140 100 170 163 200 198 191 300 216 209 400231 224 500 254 243

As the fluid enters the system, it may pass through a filter (F1) 130(FIG. 6) for solid contaminants removal, before continuing into the heatexchanger 12. The heat exchanger 12 both (a) preheats fluid prior toentering the heating section 14 and (b) cools outflow of the heatingsection 14, by enabling heat transfer therebetween. In the exemplaryembodiment, fluid enters the system at ambient, typically between 15° C.and 20° C., as measured by TC1 37 disposed along the flow path betweenthe inlet 30 and the heat exchanger 12. The fluid then flows through theheat exchanger 12, in which it is preheated to a temperature betweenapproximately 70° C. and 95° C., and more preferably between 88° C. and92° C., or approximately 90° C. In the event the ambient inlettemperature is lower than 15-20 C, a preheat section may beincorporated.

The system provides a flow path operable in a continuous and/or batchmanner from the inlet 10 to the outlets 17, 18. The flow path comprisescomponents and pipes configured to maintain the fluid at the prescribedpressure and temperatures. In the exemplary embodiment, food-gradestainless steel piping is used in the system, from the inlet to theoutlets, including the heating section. The choice of metal used in thematerials throughout the system will be based on the requirements whichbest suit the particular application, but typically will be a hightemperature alloy. This permits ease of installation with typicalapparatus without creating a metal mismatch that could produce corrosionof the metal, due perhaps to chemical or electrochemical reactionswithin the system.

In another embodiment, variable speed pumps can be used to achieve adesired pressure in the system. For example, a variable speed pump canbe used proximate to the inlet of the system 30 to achieve a desiredinlet pressure. In addition, a variable speed pump can be placedproximate to an outlet of the system and operated in association withthe inlet pressure to achieve a desired outlet pressure, but not createan internal pressure upset.

In another embodiment, best seen in FIG. 5, a heating element 112 isused to pre-heat the fluid to an even greater temperature after itleaves the heat exchanger 12. After passing through this first heatingelement 112 (e.g., tape heaters) in the pre-heating section 111, thefluid then flows into the heating section 14 and through the heatingapparatus therein 113, to be brought up to its desired temperature forsterilization. As shown in FIG. 8, heater tape is used as thepre-heating element 112 in this embodiment, although other heatingapparatus may be used, similar to the primary heating section 14 asdiscussed below. This pre-heating section 111 heats the fluid to atemperature between approximately 90° C. and 120° C., as measured by asecond thermocouple (TC2) 42 disposed along the flow path between theheat exchanger 12 and the heating section 14. Other embodiments areenvisioned, however, in which fluid passes directly from the heatexchanger 12 to the heating section 14, or even directly from the inlet30 to the heating section 14, obviating a pre-heating section 111.

A relief valve (RV1) 41 is disposed along the flow path between the heatexchanger 12 and the heating section 14 so as to release fluid from theflow path if the pressure in the flow path exceeds a set crackingpressure (e.g., 500 psig). The actuation of a relief valve diverts fluidout of the flow path so that the pressure in the flow path will stoprising or decrease, in order to protect the system from damage orfailure from excessive pressure. If actuated, the relief valves maydivert excess fluid back to the system through an auxiliary flow path,or may divert excess fluid out of the system.

The heating elements are configured to bring the fluid up to the desiredtemperature quickly and accurately. In the exemplary embodiment, shownin FIG. 2, the heating section 14 utilizes immersion fluid heaters 47,49, and 51, e.g., 1000-watt, as the primary heating element. Otherembodiments described herein may use inductive heat exchangers 132 (FIG.6), surface heat exchangers 145 (FIG. 8), or propane heaters 160 (FIGS.11, 19, 24, and 25). However, other heating apparatus may be used,singly or in combination, without departing from the scope of theinvention, such as tape heaters, heating rods, direct flame (e.g., usingnatural gas, propane, firewood or other fuels), immersion heaters,graphene (e.g., as a conductor or to administer direct heat or both),microwave, solar heaters (e.g. lenses or mirrors to concentrate heatenergy), or heat from combined heat and power generators.

In addition, systems in accordance with the invention can be integratedinto other mechanical structures, utilizing heat sources availabletherein to provide a heat source for the heating section. For example,the heating section can utilize heated components of a motorized vehicleor generator (e.g., the engine block or tailpipe) as a surface heater,so long as the desired heat can be achieved. In an exemplary embodiment,the heating section can include a flow path incorporated into a manifoldintegrated with heated components of a motor component such as agenerator or vehicle (e.g., the engine block or tailpipe), in which thecontroller can manage flow rate through the heating section to maintainfluid at a prescribed temperature and pressure for a prescribed duration(e.g., dwell time) to sterilize the fluid. Notably, in this embodiment,temperature and pressure within the heating section can be monitored andsterilization controlled by fluid pressure and flow, throughoutoperation, while integrating the temperature of the heat supply that isdependent on operation of the motorized component.

With continued reference to FIG. 5, upon exit from the heat exchanger12, pre-heated fluid is released into the heating section 14 by way of asecond check valve (CV2) 43. Fluid is heated to between approximately135° C. to 240° C., measured by thermocouples (TC3, TC4, etc.) 48, 50,52, disposed in the heating section 14. The dwell time of fluid at 240°C. is approximately 1 second or less, although the dwell time can bealtered as needed to sterilize fluid under different process variables.

In the exemplary embodiment, fluid is not allowed to change out ofliquid state. By means of high-pressure containment, the fluid isallowed to reach high temperatures while still being maintained in aliquid state. The fluid does not need to be maintained in a liquidstate, however, especially in embodiments that are not designed withhigh-pressure flow paths. The system is configured to heat the fluid atcorresponding pressure levels to achieve effective sterilization. Moreparticularly, the system can reach desired levels to sterilize bacteria,viruses, and prions, among other infective agents and organicpollutants. Furthermore, above a prescribed temperature, the system canbreak down organic molecules.

Another embodiment is envisioned in which a distillation component isdisposed along the flow path, additionally or alternatively to a heatingsection 14. One example of such a distillation component could be avacuum chamber, which would be evacuated prior to fluid entering thechamber, in which fluid vaporizes when it enters the low pressure zonein the chamber. This vaporized fluid would be collected as distillate ata condenser before continuing in the system. Additionally, thisdistillation component can be heated to sufficiently high temperaturesas in a heating section 14, in order to function both as a distillationcomponent and as a sterilization component.

The immersion water heaters 47, 49, and 51, depicted in the embodimentin FIG. 2 are designed to sufficiently fill the volume of the flow pathin close proximity with the inner wall of the pipe(s) that define flowpath through the heating section (heaters 47, 49, and 51), in order toprovide adequate surface area for the fluid to maintain the desiredcontact with the surface of the heaters 47, 49, and 51, to ensure thatthe fluid is sufficiently heated while guarding against overheating ofthe heaters. For example, in an exemplary embodiment, the flow over thesurface of the immersion heater can match the current to the heater orthe heater will over heat if the control is set to the exit temperatureof the water, but the flow is low and not removing adequate heat fromthe heater. One method of controlling this is to provide thermocoupleson the immersion heaters to ensure that they do not overheat if thewater flow drops or is reduced.

More particularly, the immersion heaters may have an elongated,cylindrical shape, wherein the heaters are oriented in axial alignmentwith the cylindrical pipes that define the flow path through the heatingsection. In this manner, the system optimizes energy transfer betweenthe heater(s) and the fluid. The flow path in the heating section 14 canincorporate various means of increasing the efficiency of the heatingelement 12 as may be required by a particular embodiment. For example,turbulence generators such as, baffles or turbulators, may be disposedin the heating section 14 flow path to break the boundary layer of thefluid's otherwise laminar flow, or to increase the fluid's surface areathat is in direct contact with the heating element 12. As anotherexample, an internal turbulator running the length of the heatingsection 14 flow path may itself be heated as an immersion heater or asan inductive heat exchanger. Furthermore, the dimensions of the heatingsection 14 in any particular embodiment can be altered to suit thedesired output quantities. For example, the length of the heatingsection 14 can be decreased for a more compact or portable systemembodiment, or the diameter of the flow path therein 14 can be increasedfor a larger and higher-capacity system embodiment. Any dimensions canbe scaled up or down to attain the desired operating variables.

The heated fluid, now sterile, exits the heating section 14 and travelsback to the heat exchanger 12. In the exemplary embodiment, the heatexchanger 12 is multi-piped, allowing for the compartmentalized flow offluid entering from the inlet 30, and heated fluid entering from theheating section 14. The proximity of the unheated fluid entering theheat exchanger 12 from the inlet 30 aids the process of cooling theheated fluid entering from the heating section 14, but thecompartmentalization prevents any possible recontamination. In otherembodiments, other means of heat transfer and heat exchanger design canbe used without departing from the invention. For example, plate-basedheat exchangers or phase-change heat exchangers may be used, singularlyor in combination, instead of or in addition to tubular heat exchangers.

In this exemplary embodiment, the temperature of the sterile fluid isreduced to approximately 70° C. after passing through the heat exchanger12. Another embodiment, seen in FIG. 6 and FIG. 7, incorporates acooling section 135, comprising fluid cooling apparatus 138, to furtherreduce the temperature of the sterile fluid before exiting the system.The fluid is passed through another relief valve (RV2) 54 (FIG. 2) and astepper motor proportional flow valve (SMPFV1) 57, before being directedthrough either a latch valve (LV2) 58 for off-spec discharge 19, or alatch valve (LV1) 60 for sterile fluid discharge 20 to exit the system.Alternatively or additionally, one three-way valve 118 (FIG. 6) could beused to direct fluid to either the off-spec discharge 19 or sterilizedfluid discharge 20 flow path. The off-spec discharge 19 may be directedto exit the system, or may be directed back into the system forre-sterilization.

Although the exemplary embodiment has been described as utilizing a pump34 to ensure adequate pressure at the inlet 30, the system can be usedwithout pumps, as seen in FIG. 9 and FIG. 10 wherein the fluid isintroduced via any of several pressure systems, i.e., gravity feed fromstorage tower, or elevated reservoir. When fluid reaches the prescribedsterilization temperature (e.g., 250° C.), as read by TC3 48 and TC4 50,a solenoid valve (SV1) 150 for off-spec discharge 19 is opened, and theinlet 30 is opened at the first proportional flow valve (PFV1) 110.Pressure is controlled by adjustments to PFV1 110 and the secondproportional flow valve (PFV2) 116. This creates a steady flow of fluidfrom inlet 30 to discharge 19. Once a steady flow of fluid isestablished for a prescribed period of time in the heating section(e.g., dwell time) in order to ensure complete sterilization (e.g., 5seconds), without significant temperature loss (e.g., at least 240° C.maintained), as monitored by TC3 and TC4, then SV1 150 for off-specdischarge 19 is closed and a second solenoid valve (SV2) 151 for sterilefluid discharge 20 is opened. Sterile fluid is then being produced,taken in at the inlet 30 through a HV1 31, CV1 35, and PFV1 110, exitingthrough SV2 151 Although the embodiments herein are described in detailwith reference to continuous operation or to a steady flow of fluid,other embodiments in accordance with the invention can be operated in apulse or batch mode. For example, a controller 180 could be programmedto produce sterilized fluid for a given volume (e.g. 100 gallons) or agiven duration (e.g. 1 hour) and then shut off the system. As anotherexample, a manual operator could open the requisite valves to allow acertain volume of fluid into the heating section 14, then close therequisite valves for the desired dwell time to sterilize the volume offluid in the heating section 14, and finally open the requisite valvesto direct that volume of fluid to the sterile fluid discharge 20.

With reference now to FIG. 21, an exemplary sequence of operation of asystem (e.g., system (FIG. 9)) in accordance with the invention isdiscussed. First, in the exemplary embodiment, the operator verifies thesystem is operational, as discussed in detail below, and all valves areclosed. Next, verified the water source is attached to deliver water tothe system. Step 3, the terminal valves can now be opened (e.g., HV1 HV2HV3). Step 4, the control valves (e.g., PFV1, PFV2, SV1) are now openedto allow full flow through the assembly to flush out all air from theflow path. Step 5, close the control valves (e.g., PFV1, PFV2, SV1). Nowfluid will be confined within the flow path of the system, free of airtrapped therein. The controller (180) will read pressure within thesystem, e.g. via P1, to ensure that an initial minimum pressure (e.g.,at least 50 psi) is available.

If the measured initial minimum pressure is satisfactory, then at Step6, the controller activates the water heating sections, in the exemplaryembodiment, the primary heating section is set to the prescribedsterilization temperature. Step 7, when the heating sector is theprescribed sterilization temperature, (as measured, e.g., TC3, TC4), thecontrol valves (e.g., PFV1, PFV2, SV1) are opened to initiate flowthrough the system. Next, at step 8, once a stable flow fluid isestablished through the system for a sufficient period of time, e.g., atleast 5 seconds, while maintaining a sufficient sterilizationtemperature, and the valve (SV1) for the off-spec discharge can beclosed and the valves for sterilized fluid can be opened (SV2).

During operations, the controller 180 monitors the system to ensureoperational safety is maintained and to ensure that the prescribedsterilization temperatures and pressures are maintained withinprescribed tolerances. These measurements are continually monitoredthroughout operations throughout the system's for example, thetemperature within the primary heating section is preferably between240° C. and 275° C. (measured at TC3 and TC4). Also, the outflowtemperature (measured at TC5). Pressure within the system, as measuredat P1 and P2 must be less than 500 psig. In the exemplary embodimentcheck browser utilized to prevent back pressure buildup in each section.Filter (F1) is used to filter out solid contaminants from entering thesystem. The controller monitors entry water temperature at TC1, which ispreferably between 15° C. and 20° C.

FIG. 26 depicts a screenshot 400 from the controller 180 depicting astatus monitor for the system. The controller monitors the sensors andcontrols the valves, heating elements and other feature of the system.During use, the controller ensures that the system operates withinprescribed ranges for pressure and temperature to achieve the desiredlevel of sterilization without need of maintaining a fixed temperatureor a fixed pressure within any portion of the system, including theheating section. This further ensure safe operation of the system. Inthe exemplary embodiment, the measurements 410 depicted in screenshot400 are received from sensors (TC1, TC2, TC3, TC4, P1, P2, P3 of FIG.22). The controller further enables the operator to designate thesterilization set point and water flow set point (420). The controllercontinually updates its measurements and controls, e.g., as shown inFIG. 27.

FIG. 13 through FIG. 18 depict several views of an embodiment utilizinga controller 180. FIG. 13 shows the system from the perspective of thefront upper right corner. FIG. 14 shows the system from the front, whileFIG. 15 shows the system from the top. Similarly, FIG. 16 shows thesystem from the rear, while FIG. 17 shows the system from the bottom.Finally, FIG. 18 shows the system from the rear lower right corner. Inthis embodiment, the system incorporates a plurality of valves coupledto the controller 180, including valves disposed at inlet and outletpoints of the heat exchanger 12 and at inlet and outlet points of theheating section 14. The valves are operated in a controlled sequence toenable effective operation of the system to include maintaining fluidwithin the heating section 14 for the desired duration to achievesterilization. Thereafter, inlet and outlet ports are opened in asequenced manner to enable the fluid to exit the heating section 14while creating a draw received fluid from the heat exchanger 12 into theheating section 14. In this manner, the system can be operated free ofpumps, while achieving the desired pressure levels due at least in partto control them sequence operation of the valves via the controller 180.

With reference now to FIG. 3, a bifurcated fluid sterilization assembly,usable for sterilizing water, is shown similar to the aforementionedembodiments, further including multiple flow paths 81, 82, 83, 84, 86,87, 88, and 89, running in parallel through the heat exchanger 12 andthe heating section 14. Along each of the flow paths is disposed aplurality of valves, such that each flow path can be operated in anindependent manner. Operation of each of the flow paths, however, can besequenced such that continuous simultaneous operation can be achieved bythe assembly, thereby amplifying the flow throughput of the overallsystem. Moreover, the controllable operation of the parallel flow pathsenables users to tailor the system's output to satisfy users demandlevels in real time. Other embodiments can utilize bifurcated orunbifurcated flow paths as necessary to achieve different outputs. Forexample, FIG. 20 depicts a variation on the embodiment in FIG. 2 usingimmersion heaters 47, 49, 51, and 200, disposed along bifurcated flowpaths in the heating section 14.

With reference now to FIG. 4, the assembly can further include anautoclave chamber 100 to sterilize equipment or supplies (e.g., medical,surgical, such as drills, scalpels etc.). More particularly, theautoclave chamber 100 is configured to expose equipment to pressurizedfluid maintained above thresholds for temperature and pressure for aprescribed duration (e.g., dwell time) to achieve desired levels ofsterilization, while maintaining the fluid in a liquid state. Theautoclave chamber 100 provides an enclosure for receiving the equipment,which can be flooded with the pressurized fluid received from theheating section 14 for sterilization. The autoclave chamber 100 iscoupled to the heating section 14 of the assembly to receive pressurizedfluid outflow therefrom. Additional heating apparatus, 170, 171, and 172(FIG. 12), can be included in the autoclave unit 100 to ensure aconsistent temperature of the fluid or to aid with drying of sterilizedequipment.

In use, equipment is placed in the autoclave chamber 100. The chamber100 is then pressurized, filled with pressurized fluid from the heatingsection 14. Preferably, the fluid is above a minimum temperature (e.g.,141° C.), and above a minimum pressure to maintain liquid state. Theequipment is exposed for a prescribed duration (e.g., dwell time) toensure sterilization. Thereafter, fluid is drained from the autoclavechamber 100, and sterile fluid cooled from the heat exchanger 12 may bedirected into the chamber 100 to cool the equipment. The chamber 100 isthen drained of fluid, and the sterilized equipment can be removed.

The outflow from the autoclave chamber 100 can be recirculated throughthe system. In the exemplary embodiment, the outflow is directed back tothe heat exchanger 12 so that it can be recirculated to the heatexchanger 12 and the heating section 14. Alternatively, the outflow canbe directed through an off-spec discharge 19 or, since the fluid used tosterilize the equipment in the autoclave chamber is sterile, through asterile fluid discharge 20. With reference now to FIG. 5, a perspectiveview is shown of a sterilization assembly in accordance with theinvention. The system can be coupled to a fluid source and electricalpower and thereafter can quickly initiate operations. Notably, thisassembly is compact and lightweight such that it can be transported withease to virtually any location. In this manner, sterilized fluid can bemade widely available. The embodiment depicted in FIG. 5 measures lessthan 1 foot in height, less than 6 feet in length, and approximately onefoot in width, although even smaller assemblies are possible.Alternatively, even larger assemblies are possible with which to provideincreased sterilization capabilities.

A sterilization assembly embodiment may utilize various power sources.One configuration may include lithium ion batteries or other forms ofenergy storage with which to operate the sterilization assembly, or atleast to operate any electronic equipment therein. Solar panels may beincorporated to charge said batteries or to operate a controller 180 orother electronic equipment. Another configuration, seen in FIG. 11,incorporates thermoelectric generators (TEG1, TEG2, TEG3, and TEG4) 162,163, 164, and 165, in the heating section 14 to recover some of theexcess heat generated by the propane heating element 160 and 161therein, and convert it to electricity to operate the assembly'selectronic equipment. The assembly can include a plurality of batteries.In use, a subset of the plurality of batteries can be charging whileother batteries can be powering the assembly, thereafter alternate, oncethe batteries are charged. The controller can be configured to managethe batteries in this manner.

FIG. 18 depicts a more detailed diagram of the gas heater assembly 161represented in FIG. 11, such that the fluid enters a coiled loop flowpath 196 (FIG. 19), which is situated above a matching flow path forpropane or other fuel 195, flowing into the coil, 190, the latter pathhaving regularly spaced perforations 194 out of which the fuel isdirected and ignited in order to heat the fluid in the upper flow path196. See also FIG. 22 for another example of an assembly incorporating agas heating source. FIGS. 23 and 24 depict gas heater assemblies thatincorporate a coiled loop flow path configured in a frusto-conicconfiguration, situated above a matching flow path for propane or otherfuel, the latter path having regularly spaced perforations out of whichthe fuel is directed and ignited in order to heat the fluid in the upperflow path.

Another embodiment is envisioned in which a sterilization system,incorporating a system controller 180, includes a means for transmittingor receiving information regarding the system. For example, a controller180 in the system could be connected to a network to transmit sensordata to, and receive commands from, a remote operator. As anotherexample, a controller 180 in the system may be equipped to broadcast anelectromagnetic signal (e.g., radio waves) to transmit operationalstatus, output rate, or maintenance needs (e.g., readiness, system stateof health) in order to monitor the system remotely.

Referring now to FIGS. 28-29, alternative embodiments of a fluidsterilization assembly is shown integrated within a water vessel ballasttank system, wherein water stored within a ballast tank 300 issterilized by using heat recovered from heat producing equipment andelectricity generating equipment within the respective water vessel.Alternative types of water heaters, as previously disclosed, can also beemployed to heat and sterilize the water. As such, water intake into theballast tank 300 from a first location, which potentially containsbiological matter from that location, can be sterilized to a desiredlevel of sterilization prior to being discharged into the surroundingbody of water in a second location. Such desired level of sterilizationis geared to minimizing the impact of introducing foreign biologicalmatter to the ecosystem of a local body of water. The desired level ofsterilization can vary by locality, such as a country, wherein aspecific government agency designated by a country may be responsiblefor mandating and regulating such sterilization levels. For example, thedesired level of sterilization in the United States is regulated by theU.S. Coast Guard, wherein the desired level of sterilization of fluiddischarged by a ballast tank system must satisfy the followingrequirements:

TABLE 2 Ballast Tank Water Content Sterilization Requirement Organismgreater than or equal to 50 Fewer than 10 live organisms micrometers inminimal dimension per cubic meter of fluid Organisms less than 50micrometers Fewer than 10 live organisms and greater than or equal to 10per milliliter of fluid micrometers Toxicogenic Vibrio cholerae Fewerthan 1 colony forming (serotypes O1 and O139) unit per 100 mLEscherichia coli Fewer than 250 colony forming unit per 100 mLIntestinal enterococci Fewer than 100 colony forming unit per 100 mL

Referring specifically to FIG. 28, a ballast tank 300, holding the waterto be sterilized, is connected to a fluid sterilization assembly,wherein the water is drawn and pressurized via a pump 34. The exemplarysterilization assembly configuration depicted in FIG. 28, includingpiping instruments and fittings, is similar to previously depictedembodiments of the assembly, such as depicted in FIG. 2, with theexception of a hand valve (HV1) 302 downstream the pump 34, and anadditional thermocouple (TC6) 304 depicted upstream a first relief valve(RV1) 41. Moreover, as aforementioned, the water heating section 306 canemploy waste heat recovery methods to heat the water to the desiredtemperature. Waste heat can be from heat sources such as heat producingmanifolds used for operation of the water vessel, and other powergenerating equipment wherein generated electricity is used. Methods torecover such heat and power include or other machines that can generateheat, whether on-board vessel or on-shore heat sources (e.g., engines,auxiliary engines, or other machines), e.g., when the vessel is at portor combinations thereof. Moreover, heat can be generated from acombination of waste heat supplemented by another source, such aselectrical sources, among others. The water heating section 306 cancontain a plurality of water heaters 308, each employing a respectivewaste heat collector 310. The water heaters 308 can be arranged in aparallel configuration wherein the incoming water is distributed amongthe water heaters 308. Alternatively, the water heaters 308 can bearranged in series wherein the water will progressively get heated afterpassing through each successive water heater 308. Once the water haspassed through the sterilization assembly, any off-spec water will berouted back to the ballast tank 300 to be pumped through thesterilization assembly again.

Referring now to FIG. 29, an alternative embodiment of a ballast tanksystem connected to a fluid sterilization assembly is shown wherein thewater heat exchanger 312 is shown as immersed within the ballast tank300, thereby optimizing the heat recovery from the water leaving thewater heating section 306. Such optimization is due to the pipingcontaining the sterilized water that will give off heat while connectingto/from the water heat exchanger 312, and thus warming up the waterwithin the ballast tank 300 prior to being pumped. Thus, the heatrequired to sterilize the water will be less since the incoming waterwill be warmer.

It should be appreciated from the foregoing that the present inventionprovides a system and method of fluid sterilization which incorporates aheating apparatus to heat pressurized fluid above prescribed thresholdsfor temperature, pressure, and duration (e.g., dwell time) to achievedesired levels of sterilization, including a heat exchanger to both (a)preheat fluid prior to entering the heating apparatus and (b) cooloutflow of the heating apparatus, and in which fluid travels through theapparatus by operating valves forward and aft of the heating section ina controlled sequence to facilitate flow through the system whilemaintain prescribed pressure and temperature profiles. The systemoperates within prescribed ranges for pressure and temperature toachieve the desired level of sterilization without need of maintaining afixed temperature or a fixed pressure within any portion of the system,including the heating section. Moreover, embodiments in accordance withthe invention can be tailored for residential, business, or industrialuses, as desired.

The present invention has been described above in terms of presentlypreferred embodiments so that an understanding of the present inventioncan be conveyed. However, there are other embodiments not specificallydescribed herein for which the present invention is applicable.Therefore, the present invention should not to be seen as limited to theforms shown, which is to be considered illustrative rather thanrestrictive.

What is claimed is:
 1. A system for fluid sterilization for a vessel,comprising: an inlet for operative connection to a fluid source toprovide fluid along a flow path for sterilization by the system; aheating section in fluid communication with the inlet along the flowpath, the heating section is coupled to a source of heat of a vessel,the heating section heats pressurized fluid therein above prescribedthresholds for temperature, pressure, and dwell time to achieve adesired level of sterilization; a heat exchanger having a first pathdisposed in fluid communication between the inlet and the heatingsection along the flow path to preheat fluid prior to entering theheating section and having a second path positioned between the heatingsection and a system outlet along the flow path to cool outflow of theheating section prior to exiting the outlet, wherein the first path andthe second path of the heat exchanger are configured to pass heat energytherebetween; and a plurality of valves disposed along the flow path,including a first valve positioned downstream of the inlet and upstreamof the first path of the heat exchanger, a second valve positioneddownstream of the first path of the heat exchanger and upstream of theheating section, and a third valve disposed along the flow pathconfigured for proportional control of fluid flow therethrough; aplurality of sensors disposed along the flow path, including (a) atemperature sensor positioned on the flow path downstream of the heatingsection and upstream of the second path of the heat exchanger, and (b) apressure sensor; and a digital controller in operative communicationwith the plurality of sensors to receive measurements therefrom and inoperative control of at least the third valve to control flow throughthe system to ensure prescribed pressure and temperature profiles acrossprescribed ranges for pressure and temperature to achieve the desiredlevel of sterilization without need of maintaining a fixed temperatureor a fixed pressure within any portion of the system, including theheating section.
 2. The system for fluid sterilization as defined inclaim 1, wherein the source of heat comprises waste heat from an engineof the vessel.
 3. The system for fluid sterilization as defined in claim2, wherein the heating section is coupled to a manifold of the engine toheat fluid passing through the heating section.
 4. The system for fluidsterilization as defined in claim 1, wherein the heating sectionincludes therein a plurality of flow path sections configured inparallel, each flow path sections coupled to the source of waste heat.5. The system for fluid sterilization as defined in claim 1, wherein thefluid source is a ballast tank of the vessel.
 6. The system for fluidsterilization as defined in claim 5, wherein the heat exchanger isdisposed in the ballast tank.
 7. The system for fluid sterilization asdefined in claim 1, wherein the desired level of sterilization of fluidoutflow exiting the system outlet satisfies the following requirement(a) for organisms greater than or equal to 50 micrometers in minimumdimension, fewer than 10 live organisms per cubic meter of fluid, and(b) for organisms less than 50 micrometers and greater than or equal to10 micrometers, fewer than 10 live organisms per milliliter of fluid. 8.The system for fluid sterilization as defined in claim 1, wherein thefirst valve is a check valve configured for unidirectional flow.
 9. Thesystem for fluid sterilization as defined in claim 1, wherein the secondvalve is a check valve configured for unidirectional flow.
 10. Thesystem for fluid sterilization as defined in claim 1, wherein the thirdvalve is a proportional control valve.
 11. The system for fluidsterilization as defined in claim 1, wherein the pressure sensor isdisposed upstream of the heating section.
 12. The system for fluidsterilization as defined in claim 1, wherein the pressure sensor ispositioned downstream of the heating section.
 13. The system for fluidsterilization as defined in claim 1, further comprising a flow meterdisposed on the flow path upstream of the third valve.
 14. The systemfor fluid sterilization as defined in claim 1, wherein in the thirdvalve is positioned downstream of the second path of the heat exchanger.15. The system for fluid sterilization as defined in claim 1, whereinthe first valve is a check valve configured for unidirectional flow, thesecond valve is a check valve configured for unidirectional flow, andthe third valve is a proportional control valve.
 16. The system forfluid sterilization as defined in claim 15, further comprising a flowmeter disposed on the flow path upstream of the third valve.
 17. Thesystem for fluid sterilization as defined in claim 15, wherein in thethird valve is positioned downstream of the second path of the heatexchanger.
 18. The system for fluid sterilization as defined in claim 1,wherein the fluid source is a ballast tank of the vessel, and the systemoutlet is in fluid communication for outflow from the vessel, enablingoutflow of ballast water that is sterilized at the desired level ofsterilization.
 19. The system for fluid sterilization as defined inclaim 18, wherein the desired level of sterilization of fluid outflowexiting the system outlet satisfies the following requirement (a) fororganisms greater than or equal to 50 micrometers in minimum dimension,fewer than 10 live organisms per cubic meter of fluid, and (b) fororganisms less than 50 micrometers and greater than or equal to 10micrometers, fewer than 10 live organisms per milliliter of fluid. 20.The system for fluid sterilization as defined in claim 1, wherein the,wherein the source of heat for the heating section comprises waste heatfrom an engine of the vessel and further comprise heat generated fromelectrical source. 21.